Carbon-doped CuFe_(2)O_(4) with C-O-M channels for enhanced Fenton-like degradation of tetracycline hydrochloride: From construction to mechanism

Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.

Significant role of carbonate radicals in tetracycline hydrochloride degradation based on solar light-driven TiO2-seashell composites:Removal and transformation pathways

TiO2-seashell composites prepared via a sol-gel method were used to generate carbonate radicals(·CO3–) under solar light irradiation. ·CO3–, a selective radical, was employed to degrade the target tetracycline hydrochloride contaminant. A series of characterizations was carried out to study the structure and composition of the synthesized TiO2-seashell composite. This material exhibits excellent solar light-driven photochemical activity in the decomposition of tetracycline hydrochloride. The possible pathway and mechanism for the photodegradation process were proposed on the basis of high-resolution electrospray ionization time-of-flight mass spectrometry experiments. Finally, we investigated the reusability of the TiO2-seashell composite. This study is expected to provide a new facile pathway for the application of ·CO3– radicals to degrade special organic pollutants in water.

Unique electronic structure of Mg/O co-decorated amorphous carbon nitride enhances the photocatalytic tetracycline hydrochloride degradation

g-C3N4 is a hot visible light photocatalyst. However, the fast recombination of photogenerated electron- hole pairs leads to unsatisfactory photocatalytic efficiencies. In this study, Mg/O co-decorated amorphous carbon nitride (labeled as MgO-CN) with a unique electronic structure was designed and prepared via a combined experimental and theoretical approach. The results showed that the MgO-CN exhibited an increased light absorption ability and promoted charge separation efficiency. The Mg and O co-decoration created a unique structure that could generate localized electrons around O atoms and enhance the reactant activation capacities via the C→O←Mg route. This could dramatically promote the O2 molecule activation on the catalyst surface to generate reactive species (?O2 –/?OH). The optimized MgO-CN exhibited a high photocatalytic activity for the degradation of tetracycline hydrochloride in water, which was five times higher than that of pristine g-C3N4. The present work could provide a new strategy for modifying the electronic structure of g-C3N4 and enhancing its performance for environmental applications.

Use of tetracycline hydrochloride and alizarin complexone for immersion marking black rockfish Sebastes schlegelii

We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles （30-40 mm total length） were immersed in a range of tetracycline hydrochloride （TC） solutions at concentrations ranging from 300 to 500 mg/L, and alizarin complexone （ALC） solutions at concentrations ranging from 200 to 400 mg/L in filtered sea water （salinity of 30） for 24 h, respectively. Otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） were sampled and used to detect fluorescent marks after a 60-day growth experiment. With the exception of 300 mg/L TC, acceptable marks were produced in the otoliths and fin spines by all concentrations of TC and ALC. In particular, we observed clearly visible marks in the sagittae, asteriscus, and fin spines under normal light at concentrations of200~00 mg/L, 250-400 mg/L, and 250-400 mg/L ALC, respectively. Scales and fin rays had acceptable marks at much higher concentrations （_〉350 mg/L TC, 〉250 mg/L ALC for scales and _〉350 mg/L TC, 〉300 mg/L ALC for fin rays）. The best mark quality （i.e., acceptable marks were observed in all sampled structures after immersion marking） were obtained following immersion in TC at between 350-500 rag/L, and ALC between 300-400 mg/L. In addition, there was no significant difference in survival and growth of TC and ALC marked fish compared to their controls up to 60 days post-marking （P〉0.05）.

Preparation of BiOCl0.9I0.1/β-Bi2O3 composite for degradation of tetracycline hydrochloride under simulated sunlight

A novel and effective BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst was synthesized through a precipitation method. The structure, morphology, and optical properties of the samples were certified by X-ray diffraction, UV-Vis diffuse reflectance, scanning electron microscopy, and X-ray photoelectron spectroscopic characterizations. Photocatalytic experiments demonstrated that the synthesized BiOCl0.9I0.1/x%β-Bi2O3 composite catalyst exhibited excellent photocatalytic performance toward the degradation of tetracycline hydrochloride(TCH) under simulated sunlight. Furthermore, the TCH degradation rate of BiOCl0.9I0.1/15%β-Bi2O3 increased by 27.6% and 61.4% compared with those of the pure BiOCl0.9I0.1 and pure β-Bi2O3, respectively. Due to the multiple vacancies and valence states possessed by BiOCl0.9I0.1/x%β-Bi2O3, namely Bi5+, Bi(3-x)+, Bi5+–O, Bi3+–O, I- and I3-, the charge separation in photocatalysis reactions can be effectively promoted. The Mott-Schottky measurements indicate that the conduction band(CB) level of BiOCl0.9I0.1/15%β-Bi2O3 becomes more negative relative to that of BiOCl0.9I0.1, guaranteeing an advantageous effect on the redox ability of the photocatalyst. This study provides a new bright spot for the construction of high-performance photocatalysts.

Application and Mechanism of ZnSb2O4 and ZnSb2O6 in the Photocatalytic Degradation of Tetracycline Hydrochloride

The photocatalytic performances in the photocatalytic degradation of tetracycline hydrochloride(TC) of ZnSb2O4 and ZnSb2O6 synthesized by hydrothermal method were explored.The effects of synthesis conditions including reaction temperature, reaction time, precursor solution pH, and the amount of hydrazine hydrate on the photocatalytic activity were discussed.The ZnSb2O4 and ZnSb2O6 photocatalysts prepared under optimal conditions exhibited similar photocatalytic activities for the degradation of TC. However, the areal photoctalytic activity of ZnSb2O4 was 12 times higher than that of ZnSb2O6 because of their different electronic and geometric structures. The photocatalytic degradation mechanisms of TC over ZnSb2O4 and ZnSb2O6 were proposed. Our work will facilitate the development of composite oxides consisting of p-block metal ions as new semiconductor photocatalysts.

Plasma-catalytic degradation of tetracycline hydrochloride over Mn/γ-Al2O3 catalysts in a dielectric barrier discharge reactor

A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method.The combination of plasma and the Mn/γ-Al2O3 catalysts significantly enhanced the degradation efficiency of tetracycline hydrochloride compared to the plasma process alone,with the 10% Mn/γ-Al2O3 catalyst exhibiting the best tetracycline hydrochloride degradation efficiency.A maximum degradation efficiency of 99.3% can be achieved after 5 min oxidation and a discharge power of 1.3 W,with only 69.7% by a single plasma process.The highest energy yield of the plasma-catalytic process is 91.7 g kWh-1.Probable reaction mechanisms of the plasma-catalytic removal of tetracycline hydrochloride were also proposed.

Porous g-C3N4 with enhanced adsorption and visible-light photocatalytic performance for removing aqueous dyes and tetracycline hydrochloride

Porous g-C3N4samples were obtained by simply calcining bulk g-C3N4in static air in a muffle oven.The photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes（methylene blue and methyl orange）and tetracycline hydrochloride under visible-light irradiation（λ〉420 nm）.Compared to bulk g-C3N4,porous g-C3N4exhibited much better capability for removing these contaminants,especially under visible-light irradiation,due to the enlarged specific surface area and more efficient separation of photogenerated charge carries.In particular,porous g-C3N4obtained by calcining bulk g-C3N4in air at 525℃ showed the highest visible-light-driven catalytic activity among these samples.Superoxide radical anions（·O2^-）were found to be the primary active species responsible for photodegradation.

Preparation and Characterization of Sulfated Cellulose Nanocrystalline and its Composite Membrane for Removal of Tetracycline Hydrochloride in Water

The removal of antibiotic pollutants remaining in the environmental media has been a big challenge nowadays.Herein,we report a facile and green approach to fabricate an eco-friendly composite membrane without addition of any toxic polymers or chemical cross-linking agents to effectively remove the tetracycline hydrochloride in Water.Firstly,the sulfated cellulose nanocrystalline(CNC) was obtained via hydrolysis of sulfuric acid by using microcrystalline cellulose(MCC) as raw material under ultrasonic condition.The as-prepared CNC has a nanowhisker dimension with 200.2 ± 110.2 nm in length,15.7 ± 9.3 nm in width,and 7.2 ± 3.1 nm in height.The obtained CNC is cellulose type I as determined by X-ray diffraction(XRD),while its crystallinity index(Crl) can reach 82.3%.Then,the composite membrane derived from the obtained CNC and commercial mixed cellulose ester(MCE)membrane was facilely prepared through vacuum dewatering process,which is applied to remove tetracycline hydrochloride(Th) in solution.The results showed that the removal efficiency of Th through the neat MCE was only28 ± 4%,while it could be improved to 58 ± 5% and 89 11%,respectively,by filtering through composite membranes with different contents of CNC deposition.Such effect is derived from the combine factors based on both steric hindrance(sieving) and electrostatic interaction(Donnan) effect of the composite membranes.The development of related CNC materials and composite fabrication processes is in favor of cost-effective and "green"polymer composites for the remediation of increasing antibiotic pollution and the purification of contaminated water nowadays.

Using Goethite as a Heterogeneous Fenton Catalyst for The Removal of Tetracycline Hydrochloride: Effects of Its Adsorptive and Reductive Activities

The removal of the antibiotic compound tetracycline hydrochloride (TC) was investigated by using goethite/H2O2 as a heterogeneous Fenton reagent. Five principle operational parameters, especially solution pH value, were taken into account to investigate how the heterogeneous Fenton process factors mediated the TC removal. This process was effective but seriously impacted by the pH value and temperature, as well as the dosages of α-FeOOH, TC and H2O2. Very interestingly, the acidic and alkaline aqueous medium conditions were both very favorable due to the occurrence of transformation of Fe(III) to Fe(II) on goethite surfaces reduced by TC at pH 3.0~4.0 even though with a low adsorption capacity of TC because its maximum adsorption of negatively charged form occurred at pH around 8.0[1], thereby greatly promoting the TC Fenton oxidative elimination. However, a rapid initial TC decay was observed at the first 5 min, followed by a much slower retardation stage, which was likely because the reductive transformation of Fe(III) to Fe(II) by TC in the solution was inhibited as the Fenton reaction proceeded. Moreover, the hydroxyl radical scavenger t-butanol addition can decrease the removal rate of TC in the goethite/H2O2 system to a certain extent. This further indicated that the main reactive species in this process were hydroxyl radicals[2]. All the goethite-catalysed heterogeneous Fenton reactions are responsible for the TC removal following the Langmuir-Hinshelwood model, were well fitted to pseudo-first order kinetics (R2】0.99), and their apparent activation energy (E) for this Fenton-like reaction was 31.86 kJ mol 1, a low value that is highly consistent with the ease of TC decay greatly enhanced by the temperature rise, indicated that the interfacial controlling interactions such as a proton induced solubilization and a reductive dissolution of goethite can clearly improve its Fenton catalytic activity[3], and these dissolution processes may not be effective in some cases, while the TC adsorption process may always play an important role to control the TC removal rate during the Fenton reaction.

In Vitro Dissolution Kinetics of α-TCP Cement Containing Tetracycline Hydrochloride

In vitro dissolution kinetics of a-tricalcium phosphate （α-TCP） cement and α-TCP cement containing tetracycline Hydrochloride（TTCH） were studied in the present paper. It shows that dissolution process of α-TCP cement and TTCH-loaded α-TCP cement accords with Avrami dissolution kinetics model： x=1-exp（-kt^n）, and Avrami constant n is 0.5 and 0.4 respectively, which means dissolution process is diffusion control. Apparent dissolution activation energy of α-TCP cement and TTCH-loaded α-TCP cement is about 9.87 kJ/moland 7.17 kJ/mol respectively. Comparing with α-TCP cement, activation energy and Avrami constant of TTCH-loaded α-TCP cement decrease slightly, but its [Ca^2＋] solubility decreases from 40 ppm to 11.5 ppm, which could result from the change of interracial property and morphology of hydrated apatite crystal caused by absorption of TTCH on the apatite.

Photocatalytic Performance of α- and β-Ga_2O_3 for the Degradation of Tetracycline Hydrochloride in Water

α- and β-Ga2O3 were prepared via a precipitation method. The as-prepared α- and β-Ga2O3 were characterized by X-ray diffraction （XRD）, N2-sorption BET surface area, UV-vis diffuse reflectance spectra （DRS）, photoluminescence spectroscopy （PL） and electron spin resonancespectroscopy （ESR）. The photocatalytic activities of Ga2O3 were evaluated by the photocatalytic degradation of tetracycline sydrochloride solution. The results showed that the photocatalytic activity of β-Ga2O3 was higher than that of α-Ga2O3 and β-Ga2O3 obtained at the calcination temperature of 900℃, which showed the best photocatalytic activity. The reasons for the differences in photocatalytic activity of Ga2O3 are discussed in terms of crystallinity, surface area, crystals and electronic structures.

Low Molecular Weight Poly(Lactide-<i>co</i>-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

The use of biopolymers as bioadhesives for human tissue is becoming a preferred alternative to suturing due to their superior adhesive, biocompatible, and biodegradable properties. In this work, low molecular weight poly(L-lactide-co-ε-caprolactone) (P(LA-co-CL) was synthesized to achieve the glass transition temperature (Tg) of the copolymer at ambient temperature so that during application on the skin, the copolymer when combined with chitosan (CHI) into the CHI/P(LA-co-CL) film could provide the strong support at the injury site. Using alcohols with different numbers of hydroxyl groups as the co-initiator in polymerization provided the distinctive characteristics of copolymers. Among all copolymers synthesized, P(LA-co-CL) copolymer using pentaerythritol as the co-initiator when combined with CHI at the ratio of copolymer/CHI at 70/30 yielded the good film properties in tissue adhesion and tetracycline hydrochloride release.

Killing effect of TNF-related apoptosis inducing ligand regulated by tetracycline on gastric cancer cell line NCI-N87

AIM: To clone the cDNA fragment of human TRAIL (TNF-related apoptosis inducing ligand) into a tetracycline-regulated gene expression system, the RevTet-On system, transduce expression vectors into a gastric carcinoma cell line-NCI-N87 and examine the effects of controlled expression of TRAIL in vitro on the gastric carcinoma cells. METHODS: The full-length cDNA of TRAIL was inserted into a vector under the control of the tetracycline-responsive element (TRE) to obtain the plasmid pRevTRE-TRAIL, which was transfected into a packaging cell line PT67. In addition, vector pRev-Tet On and pRevTRE were also transfected into PT67 separately. After hygromycin and G418 selection, the viral titer was determined. The medium containing retroviral vectors was collected and used to transduce a gastric carcinoma cell line NCI-N87. The resulting cell line NCI-N87-Tet On TRE-TRAIL and a control cell line, NCI-N87 Tet On-TRE, were established. TRAIL expression in the cell line was induced by incubating cells with doxycycline (Dox), which is a tetracycline analogue. The killing effect on gastric carcinoma cells was analyzed after induction. RESULTS: The recombinant plasmid pRev-TRE-TRAIL was constructed. After hygromycin or G418 selection, the producer cell lines PT67-TRE, PT67-TRE-TRAIL and PT67-Tet On were obtained,with titers of about 10(8)CFU.L(-1). By transducing NCI-N87 cells with retroviral vectors from these cell lines, stable cell lines NCI-N87-Tet-On TRE-TRAIL (NN3T) and control cell line NCI-N87-Tet-On-TRE (NN2T) were established. The growth curves of the selected cell lines were the same with the wild type NCI-N87. When Dox was added, cell death was obvious in the test groups (29%-77%), whereas no difference was observed in control and wild type cell lines. With the addition of a medium from the test group, human leukemia cell line Jurkat was activated till death (83%), indicating the secretion of active TRAIL proteins from the test cells to the medium. CONCLUSION: With the use of the RevTet-On system, a regulated expression system for TRAIL was constructed. Using this system, the selected killing effect of TRAIL on gastric carcinoma cell line NCI-N87 could be observed.

Efficient removal of tetracycline hydrochloride through novel Fe/BiOBr/Bi_(2)WO_(6) photocatalyst prepared by dual-strategy under visible-light irradiation

It is important to investigate whether combining two modification strategies has a synergistic effect on the activity of photocatalysts.In this manuscript,Fe-doped BiOBr/Bi_(2)WO_(6) heterojunctions were synthesized by a one-pot solvothermal method,and excellent photocatalytic performance was obtained for the degradation of tetracycline hydrochloride(TCH)in water without the addition of surfactant.Combining experiments and characterization,the synergistic effect between Fe ion doping and the BiOBr/Bi_(2)WO_(6) heterojunction was elucidated.The Fe/BiOBr/Bi_(2)WO_(6) composite photocatalyst had a beneficial void structure,enhanced visible light response,and could inhibit the recombination of photogenerated support well,which improved the photocatalytic activity.The presented experiments demonstrate that Fe/BiOBr/Bi_(2)WO_(6) removes 97% of TCH from aqueous solution,while pure BiOBr and Bi_(2)WO_(6) only remove 56% and 65% of TCH,respectively.Finally,the separation and transfer mechanisms of photoexcited carriers were determined in conjunction with the experimental results.This study provides a new direction for the design of efficient photocatalysts through the use of a dual co-modification strategy.

Construction of ternary CuO/CuFe_(2)O_(4)/g-C_(3)N_(4)composite and its enhanced photocatalytic degradation of tetracycline hydrochloride with persulfate under simulated sunlight

In this study,a graphitic carbon nitride(g-C_(3)N_(4))based ternary catalyst Cu O/Cu Fe_(2)O_(4)/gC_(3)N_(4)(CCCN)is successfully prepared thorough calcination method.After confirming the structure and composition of CCCN,the as-synthesized composites are utilized to activate persulfate(PS)for the degradation of organic contaminant.While using tetracycline hydrochloride(TC)as pollutant surrogate,the effects of initial p H,PS and catalyst concentration on the degradation rate are systematically studied.Under the optimized reaction condition,CCCN/PS is able to give 99%degradation extent and 74%chemical oxygen demand removal in assistance of simulated solar light,both of which are apparently greater than that of either Cu O/Cu Fe_(2)O_(4)and pristine g-C_(3)N_(4).The great improvement in degradation can be assignable to the effective separation of photoinduced carriers thanks to the integration between Cu O/Cu Fe_(2)O_(4)and g-C_(3)N_(4),as well as the increased reaction sites given by the g-C_(3)N_(4)substrate.Moreover,the scavenging trials imply that the major oxidative matters involved in the decomposition are hydroxyl radicals(·OH),superoxide radicals(·O_(2)^(-))and photo-induced holes(h^(+)).

Multi-walled carbon nanotubes based catalyst plasmon resonance light scattering analysis of tetracycline hydrochloride

It was found that multi-walled carbon nanotubes (MWNTs) could catalyze the redox reaction between chlorauric acid (HAuCl4) and reductive drugs such as tetracycline hydrochloride (TC), producing gold nanoparticles (Au NPs). By measuring the plasmon resonance light scattering (PRLS) signals of the resulting Au NPs, tetracycline hydrochloride can be detected simply and rapidly with a linear range of 4―26 μmol/L, a correlated coefficient (r ) of 0.9955, and a limit of detection (3σ) of 6.0 nmol/L. This method has been successfully applied to the detection of tetracycline hydrochloride tablets in clinic with the recovery of 101.9% and that of fresh urine samples with the recovery of 98.3%―102.0%.

Degradation of tetracycline hydrochloride by ultrafine TiO_(2) nanoparticles modified g-C_(3)N_(4) heterojunction photocatalyst:Influencing factors,products and mechanism insight

The unique heterojunction photocatalyst of graphite carbon nitride (g-C_(3)N_(4)) modified ultrafine TiO_(2) (g-C_(3)N_(4)/TiO_(2)) was successfully fabricated by electrochemical etching and co-annealing method. However, the effects of various environmental factors on the degradation of TC by g-C_(3)N_(4)/TiO_(2) and the internal reaction mechanism are still unclear. In this study, the effects of initial pH, anions, and cations on the photocatalytic degradation of tetracycline hydrochloride (TC) by g-C_(3)N_(4)/TiO_(2) were systematically explored, and the scavenging experiment and intermediate detection were conducted to better reveal the mechanism on photocatalytic degradation of TC. The results showed that the removal efficiency of photocatalytic degradation of TC by g-C_(3)N_(4)/TiO_(2) could reach 99.04% under Xenon lamp irradiation within 120 min. The unique g-C_(3)N_(4)/TiO_(2) heterojunction photocatalyst showed excellent photocatalytic performance for the degradation of TC at pH 3~7, and possesses outstanding anti-interference ability to NO_(3)^(-), Cl^(-), Na^(+), Ca^(2+) and Mg^(2+) ions in natural waters during the photocatalytic degradation TC process. Superoxide radicals (O_(2)^(·-)) and hydroxyl radicals (^(·)OH) were proved as the main reactive species for TC degradation, and the possible mechanism of the unique photocatalytic system for g-C_(3)N_(4)/TiO_(2) was also proposed. The above results can provide a reliable basis and theoretical guidance for the design and application of visible photocatalyst with high activity to degrade the actual wastewater containing TC.

New insights on the enhanced non-hydroxyl radical contribution under copper promoted TiO_(2)/GO for the photodegradation of tetracycline hydrochloride

TiO_(2)/graphene oxide(GO)as photocatalyst in the photo-degradation of multitudinous pollutants has been extensively studied.But its low photocatalytic efficiency is attributed to the high band gap energy which lead to low light utilization.Cu-TiO_(2)/GO was synthesized via the impregnation methods to enhance the catalytic performance.The Cu-TiO_(2)/GO reaction rate constant for photo-degradation of pollutants(tetracycline hydrochloride,TC)was about 1.4 times that of TiO_(2)/GO.In 90 min,the removal ratio of Cu-TiO_(2)/GO for TC was 98%,and the maximum degradation ratio occurred at p H 5.After five cycles,the removal ratio of Cu-Ti O_(2)/GO still exceeded 98%.UV-visible adsorption spectra of Cu-Ti O_(2)/GO showed that its band gap was narrower than TiO_(2)/GO.Electron paramagnetic resonance(EPR)spectra test illustrated the generation rate of·O_(2)^(-)and·OH was higher in Cu-TiO_(2)/GO system than TiO_(2)/GO and TiO_(2) system.The contribution sequence of oxidative species was·O_(2)^(-)>holes(h+)>·OH in both TiO_(2)/GO and Cu-Ti O_(2)/GO system.Interestingly,the contribution of·OH in Cu-TiO_(2)/GO was less than that in TiO_(2)/GO during the photo-degradation process.This phenomenon was attributed to the better adsorption performance of Cu-Ti O_(2)/GO which could reduce the accessibility of TC to·OH in liquid.The enhanced non-hydroxyl radical contribution could be attributed to that the more other active species or sites on(nearby)the surface of Cu-TiO_(2)/GO generated after doping Cu.These results provide a new perspective for the tradition metal-doped conventional catalysts to enhance the removal of organic pollutants in the environment.

In-situ construction of Co(OH)_(2) nanoparticles decorated biochar for highly efficient degradation of tetracycline hydrochloride via peracetic acid activation

Peracetic acid(CH_(3)C(O)OOH,PAA)-based heterogeneous advanced oxidation process(AOP)has attacked intensive interests due to production of various reactive species.Herein,Co(OH)_(2)nanoparticles decorated biochar(Co(OH)_(2)/BC)was fabricated by a simple and controllable method,which was used to degrade tetracycline hydrochloride(TTCH)in water through PAA activation.The results indicated that 100%TTCH(C_(0)=10μmol/L)degradation efficiency was realized within 7 min at pH 7,with a high kinetic rate constant(k_(1))of 0.64 min^(-1)by the optimized Co(OH)_(2)/BC.Material characterizations suggested that Co(OH)_(2)nanoparticle was successfully decorated on biochar,leading to more active sites and electronic structure alteration of biochar,thus greatly promoting the catalytic cleavage of PAA for radicals production.Then,the reactive oxygen species(ROS)quenching experiments and electron paramagnetic resonance(EPR)analysis demonstrated the key species were alkoxyl radicals(R–O^(·),mainly CH_(3)CO_(2)^(·)and CH_(3)CO_(3)^(·)),HO^(·)and^(1)O_(2)in this system.Besides,density functional theory(DFT)calculation on Fukui index further revealed that the vulnerable sites of TTCH and three possible degradation pathways were proposed.This study can provide a new strategy for synthesis functional materials in PAA activation AOPs for removal of antibiotics in water.